Eye model



l f 1,630,944',"v j; i

.May 31.1927.'

A R. INGERsoLL.

EYE: MODEL Filed Oct. 19. 1925 l vPatented May 3.1, 11927; Y

.i "EYE iiion'iin.'y y

Appiiationfiiea etoberis, 19251 rserial'im.153,407.' :f 'i

*Y The invention'relatesjto.an improvement in models to villustratethe action of the eyev @as an optical instrument, for .purjpovseso'i eX- perimental demonstration Iand;` instruction. lt .may be briefly describedTas-any apparatus,

external object is caused toffallbn a" screen m 'or retina so .that 'it vcan be observed vvand f studied(V Wvith the aidoil-.various lenses and` other auxiliary-.apparatus,` describedlater,

i' it is thus possible, to illustrateand study the simplev optical principles of the` normal eye, as well .as thegcause of and `correction flor such detects as ynear-sightedness, fiar-,sights edness and astigmatism., lmportant features` not the improved apparatusare that it isso designed Vthatdarkening of theroomis un- 20 o in the actual eye, thus rendering'the demonthat it isof relatively unbreakable construction; thatit is suitable foro bservation by,v thel demonstrator for instructor and by Vsev-f` f leral students oron-lookers at the Sametime;

Y and` that it provides peculiarly `vconvenient` andsatisfactory 'means vof studyingthe de-,

iects., ofl :i l i'ar-sightedness,AY l. nearfsightedness and Y astigmatism Vand their correction.

`The invention in itsfessentialform lil lustrated in the accompanying drawing, in

which Fig. l is a horizontal-section .ortop addition of correcting lenses; F ig. 2 Vis a u "side View; Fig. v3 is a front view ofthe model screen. f

The detailed description is as follows?-v The body of the instrument .is a Water- 1 tight-chamber or tank-l, nearly oval 'in lsha-pe, mounted on a flat ibase 2, supported by short legs 3. This is preferably madeI of metal andl a convenient size is aboiit'S inches long. i The y'front of this artificial.` eyeball has a hole 4,*over which is fastenedY 'placedy The last guide behind the cornea avtype' of camera 'obscui"a,y somewhat like an-eyeball in shape V(although considerably y lai'ger in which anoptical imageot some-l is ,taken by Water.

.eye and; images eas't'on it are inv-isible.`-=A The -f lbottgom'y of "theeyelmodel has series `oi", dowel vpins `16,2which:engagecorresponding@ holes.17'in/theA iiatbase of the 'retina' and;rv l y fixitgfinfanybne Vof three4 positions 18, 19,*

y .20;---Positi'oni18pm'V which thek ,retinal ig -Y ystr'a'tions f and, experiments incred :graphic necessary instudying or'demonstrating it; that it approximates Vsomewhat'-closely the form, construction of,.and opticalflzonditionsjVV view of the inodelas itV appears Without-the and Fig. l ar front View of the retina 'ord' fectivelyto shut oil Yfrom considerationftlie 9! in which' guides i various is for thecrystallinelensllO, mounted inra/l circularframe 22, andthis vguide is con-:f ,-nected with a1 diaphragm ll, which divides.;V

vthe eyeball intokjtvvo parts, but. which, novi/5F60 ever, comes'fiip butlpart Way; rlhe rpurpfose ot this diaphragm isto indicate, the division V`of the eye. into the ,cliai'nbers-Which hold the e: Y

aqueous and vitreous humoiis,respectively... rihe place of these humors'in eyemoflel The' retina isac urved metalplate 12, ogni a'lat base 13,*Whieli litson the flat basent the model.. It has-a `largecirculan.,areal on its frontor vconcavesurface, paintedWhite so kthat iniages-ormed on it iaie readily visible, with blackf-spotfl5,fonone siday This represent-stile `blind spot', of thereal shown in `thetigure, gives what maygvbe'.ref9 0` garded' as the eyeballof -normallength posiltion 19 slio'rtjens` the eyeball by a givenif' a amount Yand gives. kthe e'tlect r of far-sighted l lvision '(hypermetropia) ,jwliile20v lengthensA it` by the 'same Aamount* and makes the eye 85 myopic'ror near-sighted. These-'three pdis'ej" `crete.positions,in' lWliichf the retina :may-be Y ...fixed Ab.yl.- dowel pinsl are'regarded as yes;-;: ,"sential l'features -ot'. 'this .eye niodel, for theyfg really O'ive theA observer three dililerentfeye-.y balls, fiaA e., normal, 'farfsighted and near"- sighted,l\vitli Vivhichto `Worin..Toimake this' A feature .more effective, the'V retina ina-lies close l ContactA-With thes'ides of the ey'e-sojasjetv- 1 part back of it.. Toallowchange of thel [retina from one position to another VWithout 'splashingwater it has a number of marginal;

holes 21.

4' Ihefdoivel zpins 16 senve,another:.useful-1l that focussing could bedone byA moving ythe :retina alone; for in the real` eyeaccommoda. f [tion or focussing Ais brought-about by cliangesjm'r 'in the curvature of the crystalline lens,`1the retina being fixed. Accordingly in thiseye model,fto approximate'as closely as possible :the true eyepconditions, 4it' is intendedfthatl .i y l focussing vshall begdone @only byv changing. 10 the crystallinelens 10, withV or Without the addition of auxiliary lenses. I e

no v`.purpose in that. they :prei'fent theretina from Vbeing moved by.continuous,adjustment so- The followingauXiliary apparatusis re# qiiired.,for.use with kthis eye model (l) A set of six lenses,'mounted in circular metal frames to'iit. into the guides, .of the following sorts V:l-Ti'i'roV convex sphericalk lenses of different focal lengths to Vbe usedya's. 'weak and strong crystallinelenses; convex and concave sphericaldenses-for correcting` farand near-sightedness, respectively; ak

strong concave cylindrical lens for producing astigmatism andv a convex Vcylindrical Vlens for correcting" it. These lenses must be n 1 Vof certain definite focal lengths, depending on the actual/size of the model. In addition tothese lenses is a diaphragm with 'liole smaller `in size tlianefwhicli when usedin Aonevof the guides .8, lactslas a pupil of dimin- Y. v(27) A light source consistingV of an incan# descent lampf-in a boi;` having` al window shapedl like'qan'- eight-armed cross, with a ,Y ground-glass=diffusing screen behind it.

'V 1 The modell is used in the following way VVItisy first filled nearly 'fulljof Clearwater 'to represent thev aqueousl and vitreous humors of the actual eye and; is thenV placed facing 'a windowV or other bright 'objecta given dis-V tance away.` Theweakerfcrystalline lensis thenrinserted"behindthe cornea and this is its;- inverted character, whatv` happens when it fallson the blindspot,y etc.,v can thenbe' studied. #The generalform ofthis eye model andthe factthat it is open Vonly atthetop kof'suchv strength that aclear image isformed on'the retina if this-'is inV position'l-Sf- (normali eye). T'Ifhe'f main characteristics of thisimage,Y

n v makesfit'peculiarly-easy to-study this image without darkeningthe roomiinanyfway, and

this is avery important featurev as it allows the-use of thelfmodel in a large generallaboeratory where studentsmay be working atmany, other tasks and ywhere darkening l ofY 1 the room Wouldfnot be feasible.

With thek aidl of the lensesand lamp box.

- already-mentioned the main opticalfeatures off the eye may then bestudied; .including accommodation', farand near-sightedness, and their correction,4 astigmatismV (which is producedinfthis case by inserting thestrong cylindrical lensxbehiiid thecorneai) andiitsl correctioin vision without crystalline lens- (as after operation for cataract), compound de'-I fects,'and the-action of the simple magnifier.

claims.

Iclaim: V' ,.7 l'. 'An eye modell comprising a. vesselwitli opaque vertical walls,.open at'the-topyrepre-l senting the eyeball, vhavingiin horizontal .y the generalslia'p'e ofg thelliumafni'eye grani aperel section, and onlyiinV horizontal section, the general shape of thehunian eye, saidcvessel, to be water-tight andvdesigned for filling witliwater ,orfother transparent liquid Vto represent Mthe Vliuinors 'of` the eye; an apertu-rezan the front of said vessel representingV the pupil; a glass lensfastened over said apertiire,.representingthecorneag a seriesfof l .Y Y racks or guides in front Aof and behindV said cornea for holding otherlenses; aremovable` and a movablecurvedtransverse opaqueseparating member iepi'esentingfthc retinal` 2. An eye model comprising a water-tight ing in horizontal sectioinbnly', the generalvglass `lens representingftlie crystallineflens;

kVessel with opaque vertical walls, open aitithe4` l top, representingthe Veyebalhsaid vessel hav# shape offthe humanV eye; anI aperture represa *senting the pupi-l; lenses repi'fesentingythe' corlnea and` crystalline lens; guidesforholdi' j ingother lenses a transverse opaque `member: representing-the retinag and separating diaphragm toindicate the division oftheV eye intothe chambers which hold the-"aque-V ous'andvitreous humors, such vhumorsin*V this 4case to be represented'byfw'ater or'other f i im Y.

.transparentlliquid;l i .f

3. An eye model comprising a walteretight;V

ingly the eyebally-said vessel beingf open at the top il and hav-ingl in horizontal i section,` only; Y

vessel with opaque veiticalwalls,f.represent-I..

ture; representing -the'ffpupilgatone 'endfoff Y saidvessel, forl admitting',raysoffliglit;v aw

oversaid apertureg representing tl'i' e"c'ornea;-v racks orl guides in frontiofsaidapertureandi lens fastenedv on theoutside of 'said fveSselAA outside 'said' vesselyV for-'1: holding various-f; lenses g* racks igor guides :behind said aperture andwithin` saidfvessell for holding lenses.;4 a1

`second lens removably mounted inl saidracks'. within saidv vessel, representing" the crystalf`105 'A line lens; andracurved;"tnansveiise opaques member7 representing th'e retina, having 1' its f i concave' surface towards the crystallinelens7 saidi concave sur-facebeingl whiter save fori alA blackv spot to ij'epresentthe blind spot offtheV eye;l

l. An eye model .comprising a watelf-tight?iv :vessel with opaque vertical walls-, representing't'heeyeballg saidv vesselibeing openfatvthe' top and'having in horizontal sectiong'jonly,

the generalshapefof thehumanreye; an aper; f

ing .the corneaandf."crystalline lensggnides l ture lrepresentingthe pupil; lenses represent'- l for holding lenses; a. transverse scrJeen'rep-zl resentingy the-rretina; and: means for locatL ing said screen` at vthree discrete positions,

whereby three denite'l'engths ofeyebalilvmay 1 be represented and? thel optical characteristhespecifications.`

LEONARD ROSE INGERSQLL..

'ticsvthereof lstudied as further describedinjl 

